DESCRIPTION:(provided by applicant) The major objective of this research is to gain a better understanding of locomotor adaptations made in response to altered sensory inputs. The proposed studies focus on the role of sensory information relayed from the "feet up" in the adaptation of locomotor trajectory. Recent work has shown that, following podokinetic stimulation (i.e., stepping in-place on a rotating treadmill for 20-40 minutes), blindfolded subjects asked to step in-place or walk in a straight line on a stationary surface will unknowingly rotate relative to space. This adaptation, called podokinetic after-rotation (PKAR), has two distinct components: 1) a short-term effect with a time constant of 5-10 minutes and 2) a long-term effect with a time constant of 1-2 hours. A more complete understanding of PKAR may be useful for developing rehabilitation strategies for people with balance and gait disorders. The proposed experiments will use podokinetic stimulation as a means of assessing the effects of altered sensory inputs on the control of orientation during locomotion. Specific Aim I examines the kinematic and electromyographic features of PKAR. Specific Aim 2 addresses the generalizability of adaptations of forward walking to other behaviors and asks whether the left and right limbs can be independently adaptated. Specific Aim 3 explores the role of the cerebellum in the acquisition and maintenance of locomotor adaptations to podokinetic stimulation